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The Janus transcription factor HapX controls fungal adaptation to both iron starvation and iron excess.

Gsaller F, Hortschansky P, Beattie SR, Klammer V, Tuppatsch K, Lechner BE, Rietzschel N, Werner ER, Vogan AA, Chung D, Mühlenhoff U, Kato M, Cramer RA, Brakhage AA, Haas H - EMBO J. (2014)

Bottom Line: We further demonstrate that a HapX homodimer and the CCAAT-binding complex (CBC) cooperatively bind an evolutionary conserved DNA motif in a target promoter.The latter reveals the mode of discrimination between general CBC and specific HapX/CBC target genes.Collectively, our study uncovers a novel regulatory mechanism mediating both iron resistance and adaptation to iron starvation by the same transcription factor complex with activating and repressing functions depending on ambient iron availability.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria.

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HapX-mediated iron detoxification is evolutionary conservedA. nidulans and F. oxysporum deletion mutants were grown for 48 h at 37°C on agar plates with the given iron concentration.
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fig07: HapX-mediated iron detoxification is evolutionary conservedA. nidulans and F. oxysporum deletion mutants were grown for 48 h at 37°C on agar plates with the given iron concentration.

Mentions: Similar to A. fumigatus, HapX orthologs repress iron-dependent pathways and the cccA orthologs during iron starvation in A. nidulans, F. oxysporum, S. pombe, C. neoformans, and C. albicans (Mercier et al, 2006; Hortschansky et al, 2007; Jung et al, 2010; Schrettl et al, 2010; Hsu et al, 2011; Lopez-Berges et al, 2012). Here, we found that HapX-deficiency also impairs growth of A. nidulans and F. oxysporum on high-iron media (Fig7) demonstrating that the function of HapX in iron detoxification is evolutionary conserved. Inspection of genome-wide transcriptional profiling data indicated that the cccA ortholog FOXG_04047 in F. oxysporum is repressed similar to A. fumigatus during iron starvation and upregulated during iron sufficiency in a HapX-dependent manner (Lopez-Berges et al, 2012). These data suggest that in F. oxysporum the decreased iron resistance caused by HapX-deficiency also results from impaired vacuolar iron storage.


The Janus transcription factor HapX controls fungal adaptation to both iron starvation and iron excess.

Gsaller F, Hortschansky P, Beattie SR, Klammer V, Tuppatsch K, Lechner BE, Rietzschel N, Werner ER, Vogan AA, Chung D, Mühlenhoff U, Kato M, Cramer RA, Brakhage AA, Haas H - EMBO J. (2014)

HapX-mediated iron detoxification is evolutionary conservedA. nidulans and F. oxysporum deletion mutants were grown for 48 h at 37°C on agar plates with the given iron concentration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4232046&req=5

fig07: HapX-mediated iron detoxification is evolutionary conservedA. nidulans and F. oxysporum deletion mutants were grown for 48 h at 37°C on agar plates with the given iron concentration.
Mentions: Similar to A. fumigatus, HapX orthologs repress iron-dependent pathways and the cccA orthologs during iron starvation in A. nidulans, F. oxysporum, S. pombe, C. neoformans, and C. albicans (Mercier et al, 2006; Hortschansky et al, 2007; Jung et al, 2010; Schrettl et al, 2010; Hsu et al, 2011; Lopez-Berges et al, 2012). Here, we found that HapX-deficiency also impairs growth of A. nidulans and F. oxysporum on high-iron media (Fig7) demonstrating that the function of HapX in iron detoxification is evolutionary conserved. Inspection of genome-wide transcriptional profiling data indicated that the cccA ortholog FOXG_04047 in F. oxysporum is repressed similar to A. fumigatus during iron starvation and upregulated during iron sufficiency in a HapX-dependent manner (Lopez-Berges et al, 2012). These data suggest that in F. oxysporum the decreased iron resistance caused by HapX-deficiency also results from impaired vacuolar iron storage.

Bottom Line: We further demonstrate that a HapX homodimer and the CCAAT-binding complex (CBC) cooperatively bind an evolutionary conserved DNA motif in a target promoter.The latter reveals the mode of discrimination between general CBC and specific HapX/CBC target genes.Collectively, our study uncovers a novel regulatory mechanism mediating both iron resistance and adaptation to iron starvation by the same transcription factor complex with activating and repressing functions depending on ambient iron availability.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria.

Show MeSH
Related in: MedlinePlus